Spinal fixation system

ABSTRACT

A spinal fixation implant system for correction and fixation of the human spine to facilitate an anatomically correct fusion. The spinal fixation system may include a connector, a spinal rod, a spinal fixation component, and a fastener. The spinal fixation component preferably includes a fixation device such as a hook or screw for securing the spinal rod to vertebrae of the thoracic or lumbar spine. The connector preferably includes a threaded end adapted to receive the fastener and a receiving end adapted to receive the spinal rod. The fixation component may include a body having a tapered cavity for engaging the receiving end of the connector. Tightening of the fastener preferably draws the connector through the tapered cavity which compresses the receiving end about the spinal rod to fixably connect the spinal rod and the spinal fixation component.

This is a continuation of U.S. patent application Ser. No. 09/093,756filed on Jun. 6, 1998 which issued as U.S. Pat. No. 6,132,430; and whichis a divisional of U.S. patent application Ser. No. 08/740,123 filed onOct. 24, 1996 which issued as U.S. Pat. No. 6,416,515.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to spinal fixation systems andthe like. More particularly, an embodiment of the invention relates to aspinal implant system for correction, fixation, and stabilization of thehuman spine to allow the development of a solid spinal fusion.

2. Description of the Related Art

Spinal fixation, such as lumbar sacral fusion and the correction ofspinal deformities such as scoliotic curves, is a well known andfrequently used medical procedure. Pedicle, lateral, and obliquemounting devices may be used to secure corrective spinal instrumentationto a portion of the spine that has been selected to be fused byarthrodesis.

A spinal fixation system typically includes corrective spinalinstrumentation that is attached to selected vertebrae of the spine byscrews, hooks, and clamps. The corrective spinal instrumentationincludes spinal rods or plates that are generally parallel to thepatient's back. The corrective spinal instrumentation may also includetransverse connecting rods that extend between neighboring spinal rods.Spinal fixation systems are used to correct problems in the lumbar andthoracic portions of the spine, and are often installed posterior to thespine on opposite sides of the spinous process and adjacent to thetransverse process.

Various types of screws, hooks, and clamps have been used for attachingcorrective spinal instrumentation to selected portions of the patient'sspine. Examples of pedicle screws and other types of attachments areillustrated in U.S. Pat. Nos. 4,763,644; 4,805,602; 4,887,596;4,950,269; and 5,129,388. Each of these patents is incorporated byreference as if fully set forth herein.

An eyebolt assembly of the TSRH® spinal system sold by Danek MedicalInc. is illustrated in FIG. 1. The eyebolt assembly 2 encircles spinalrod 4 such that assembly mass completely surrounds the spinal rod. Thespinal rod must be inserted through the eyebolt, which rests within theyoke of spinal hook 8. The spinal hook attaches the spinal rod to a bonyelement of the spine. A nut 6 is threaded onto a post of the eyeboltassembly to fixably secure the rod within the yoke. The nut is tightenedso that the assembly resists axial, torsional, and shear forces toinhibit motion of the spinal rod relative to the assembly in thedirections indicated by the arrows in FIG. 1. Further details of theTSRH® spinal system are provided in the TSRH® Spinal Implant SystemSurgical Technique Manual and the TSRH® Crosslink Surgical TechniqueManual. Both of these publications are available from Danek Medical Inc.and are incorporated by reference as if fully set forth herein.

Manual insertion of a spinal rod through the bores of a number ofspaced-apart eyebolts within a surgical wound tends to be difficult. Thebore axis of each eyebolt must be properly aligned along a common axis,which is difficult since the corrective procedure requires that thespinal rod initially be placed under stress to resist deforming forcesof the spine. Therefore, the use of systems such as the TSRH® spinalsystem may require that a predetermined number of screws or hooks bepre-loaded onto the spinal rod in a particular order and spacing priorto the insertion of the spinal rod into the surgical wound. Afterinsertion of the spinal system into the surgical wound, however, it isoften necessary to add, delete, or reposition one or more hooks orscrews. Before such modifications can be made, the spinal systemtypically must be removed from the surgical wound and at least partiallydisassembled.

To overcome such problems, some spinal fixation systems include “openback” hooks or screws to allow a spinal rod to be dropped into the openback of the hook or screw and secured within the open back by a separatecomponent and a set screw. Such a system is illustrated in U.S. Pat. No.5,102,412 to Rogozinski, which is incorporated by reference as if fullyset forth herein. Such systems tend to be susceptible to fatigue stressfailure and require assembly within the surgical wound. In addition,adding a hook or screw to the construct tends to require that the spinalrod first be repositioned. A further disadvantage of this approach isthat component mass completely surrounds the spinal rod, resulting in anincrease in the profile width of the device and greater impingement ofthe device upon the fusion mass. A low profile width is generallydesired to minimize sinus formation and soft tissue irritation fromhardware prominence.

U.S. Pat. No. 5,242,445 to Ashman relates to a “split eyebolt” assemblyfor adding eyebolts to an assembled spinal fixation construction.Attaching the split eyebolt to a spinal rod requires a special crimpingtool to crimp the split eyebolt over the rod. The crimping tool tends tobe difficult to operate within the surgical wound. Furthermore, thethreads of the opposing sides of the split eyebolt are often misalignedafter crimping, making it difficult or impossible to thread a nut ontothe split eyebolt. The split eyebolt also completely encircles thespinal rod thereby increasing the impingement of the construct upon thefusion mass.

It is therefore desirable that an improved spinal fixation system bederived that facilitates assembly and surgical implantation by allowingthe spinal rod to be positioned within the surgical wound (a) after thefixation components (e.g., screws, hooks) have been implanted, (b)without modifying the fixation components, and (c) whereby fixationcomponents may be subsequently added, deleted, and/or repositionedwithout disassembling the system.

SUMMARY OF THE INVENTION

In accordance with the present invention, a spinal fixation system isprovided that largely eliminates or reduces the aforementioneddisadvantages of conventional spinal fixation constructions. Anembodiment of the invention relates to an implant system for fixation ofthe human spine that includes a spinal rod, a fixation component, aconnector, and a fastener.

The connector may be used to connect the spinal rod to the fixationcomponent and preferably includes a receiving end and a fastening end.The receiving end may contain a first arm and a second arm that togetherform a substantially U-shaped borehole into which the spinal rod may beaxially positioned. The receiving end preferably surrounds only part ofthe spinal rod such that the unsurrounded portion of the spinal rod isexposed from the borehole. The exposed portion of the spinal rod mayextend out of an open end of the U-shaped borehole. The spinal rod maybe circular and preferably includes a cross-section having acircumferential portion. The receiving end of the connector preferablysurrounds and engages greater than about π radians and less than about2π radians of the circumferential portion.

The receiving end of the connector preferably acts as a “pinch clamp” byexerting a clamping force on opposing sides of the spinal rod to securethe spinal rod within the borehole. The connector preferably contains aslot between the receiving end and the fastening end that enables thefirst arm and the second arm to be deflected relative to one another.The deflection of the arms allows the distance between a tip of thefirst arm and a tip of the second arm to be changed so that the spinalrod may be inserted through an open end of the U-shaped borehole that isdefined between the tips of the arms.

The fixation component preferably includes a fixation device such as abone screw or hook for engaging vertebrae of the thoracic or lumbarspine. The fixation component also preferably includes a body containinga cavity with an inner surface. The cavity is preferably sized toreceive a portion of the connector. The connector is preferablypartially disposed within the cavity such that at least a portion of thefastening end extends from the cavity, whereby the inner surface of thecavity engages an outer surface of the receiving end. The cavity of thebody is preferably a tapered cavity that narrows in a direction from afirst end of the cavity to a second end of the cavity. The taperedcavity preferably surrounds a portion of the receiving end and imparts acompressive force against the receiving end to secure the spinal rodwithin the borehole.

The fastener preferably engages both the body and the portion of thefastening end that extends from the cavity. The fastener may secure theconnector and the fixation component together. The fastener ispreferably a nut adapted to be threaded upon the fastening end. Thefastener may be selectively tightened to allow an engagement between theconnector and the spinal rod that may be overcome by the application ofa distraction force to the connector. Rotation of the nut in atightening direction about the fastening end preferably draws a portionof the receiving end through the tapered cavity, causing the innersurface of the cavity to compress the arms of the receiving end. Inturn, the arms may exert a compressive force against the spinal rod toclamp it within the borehole. The magnitude of the compressive forceagainst the spinal rod preferably varies as a function of the degree towhich the nut is tightened. The open end of the U-shaped boreholepreferably has a width that can be adjusted by tightening the fastener.

The fixation component may include a spacer located between the fastenerand the spinal rod for laterally offsetting the fixation device aselected lateral distance from the spinal rod. The spacer may include asurface having a plurality of radially-spaced teeth. The fixationcomponent may comprise a plurality of radially-spaced protrusionsadapted to fit adjacent to the teeth on the surface of the spacer. Thetightening of the nut preferably causes the spacer and the fixationcomponent to become pressed together such that a complementaryengagement between the teeth of the spacer and the protrusions of thefixation device is formed to inhibit rotation of the fixation deviceabout the spacer.

The body may include a U-shaped yoke formed between a top section and abottom section that each have an edge adjacent to the yoke. The taperedcavity preferably is formed between the top section and the bottomsection and extends in a perpendicular direction relative to theU-shaped yoke. The fixation component is preferably adapted to pivotabout the spinal rod in a substantially vertical plane. The edges of thetop and bottom sections preferably contact the spinal rod during thepivoting of the fixation component to define the range of pivotal motionof the fixation component about the spinal rod. The edges are preferablycurved in a direction away from the spinal rod to increase the range ofpivotal motion of the fixation component.

The fixation component may include a transverse connector to maintain afixed distance between the spinal rod and a neighboring spinal rod. Thetransverse connector may include a reduced section that has a width lessthan that of the body, allowing the reduced section to be more easilybent. The reduced section may be bent to shorten the lateral distancebetween the spinal rod and an adjacent spinal rod. The transverseconnector may contain a beveled section between the body and the reducedsection.

An advantage of the present invention relates to a fixation componentthat may be added to or deleted from a spinal fixation construct in asurgical wound without disassembling the construct.

Another advantage of the present invention relates to a spinal fixationsystem requiring minimal assembly within the surgical wound.

Yet another advantage of the present invention relates to a spinalfixation system having a relatively narrow profile width to reduceimpingement upon the fusion mass.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages of the present invention will become apparent tothose skilled in the art with the benefit of the following detaileddescription of the preferred embodiments and upon reference to theaccompanying drawings in which:

FIG. 1 depicts a TSRH® spinal system eyebolt assembly;

FIG. 2 depicts a side view of an embodiment of a spinal fixation systemconnected to a vertebra;

FIG. 3 depicts a top view of the spinal fixation system of FIG. 2;

FIG. 4 depicts a side view of a tapered connector constructed inaccordance with the present invention;

FIG. 5 depicts a side view of a tapered connector prior to assembly witha fixation component body and a spinal rod;

FIG. 6 depicts a side view of a tapered connector assembled with aspinal fixation component and a spinal rod;

FIG. 7 depicts a side view of a transverse connector disposed between apair of spinal rods in accordance with the present invention;

FIG. 8 depicts a front view and side view partially in section of a bonescrew constructed according to teachings of the present invention;

FIG. 9 depicts a front view and side view partially in section of a bonescrew having radially-spaced protrusions in accordance with the presentinvention;

FIG. 10 depicts a front view and a side view partially in section of areversible fixation component constructed according to teachings or thepresent invention; and

FIG. 11 depicts a side view partially in section of a spacer disposedbetween a spinal rod and a fastener in accordance with the presentinvention.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof are shown by way ofexample in the drawings and will herein be described in detail. Itshould be understood, however, that the drawings and detaileddescription thereto are not intended to limit the invention to theparticular form disclosed, but on the contrary, the intention is tocover all modifications, equivalents and alternatives falling within thespirit and scope of the present invention as defined by the appendedclaims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 2 depicts a spinal fixation system 10 constructed according toteachings of the present invention. In an embodiment of the invention,spinal fixation system 10 includes a spinal rod 12 generally alignedparallel with a portion of the spine. Connector 16 secures spinalfixation components to the spinal rod via fastener 18. The fixationcomponents may include various fixation devices including bone screw 14,transverse connector 20, and spinal hooks 22 and 24.

Spinal rod 12 is preferably constructed of stainless steel or anotherrelatively rigid material. The spinal rod preferably has a substantiallycircular cross-section (although other cross-sectional geometries may beemployed) and a diameter between about ⅛ of an inch and about ¼ of aninch. The spinal rod may have a shot-peened surface to increase itsresistance to fatigue failure. The spinal rod may impart forces againstthe spine to maintain a portion of the spine in a fixed position tocorrect a spinal deformity or injury. The spinal rod may be contoured toa selected shape prior to or after surgical implantation.

Bone screw 14 is preferably inserted within the main body of a vertebra26 and may contain threads 28 to create a fixable engagement with thevertebra. Alternatively, the bone screw may have a substantially smoothshank containing no threading. The stress imparted to spinal fixationsystems resulting from a spinal deformity may cause fatigue failure of athreaded bone screw if a solid spinal fusion does not develop after aperiod of time. Threaded screws having relatively long shanks tend tofail at a location adjacent to the screw head. A substantially smooth,unthreaded shank tends to remove the stress concentration on the screwshank from a location adjacent to the screw head where failure of thescrew often occurs. The bone screw may also include a tap relief 30 tofacilitate its insertion into vertebra 26. The angle of the bone screwrelative to the spinal rod is preferably adjustable. The bone screw maybe angled to correct the angle 32 of a vertebra relative to othervertebrae in the spine. The angle between the bone screw and spinal rodis preferably fixable by tightening fastener 18. Furthermore, the heightof the vertebra 26 may be adjusted by applying a distraction force inthe directions indicated by arrow 34 between a pair of fixation devicessuch as bone screw 14 and spinal hook 24 prior to tightening fasteners18. The distraction force may be applied with the use of a tool in amanner well known to those skilled in the art.

The spinal hooks 22 and 24 may be any of a number of types of hooks wellknown to those skilled in the art including large laminar, smalllaminar, thoracic laminar, and pedicle hooks. Each spinal hook may bepositioned in the caudal direction (illustrated by hook 24 in FIG. 2) orin the cranial direction (illustrated by hook 22 in FIG. 2). Spinalhooks may be positioned on opposing sides of the spinal rod as shown inFIG. 2.

FIG. 3 depicts a top view of an embodiment of spinal fixation system 10that includes a pair of spinal rods 12 in spaced relation on each sideof the vertical axis 40 of the spine. Spinal hooks 22 and 24 arepreferably positioned for attachment to bony elements of the posteriorhuman spine. One or more transverse connectors 20 may be used to rigidlylink the rods to improve the strength of the assembly. Each of thefixation components may be attached to the spinal rod using a fastener18 that engages connector 16 and the fixation component.

Transverse connector 20 may connect neighboring rods to increase therigidity of the construct and to prevent the movement of the rodsrelative to one another. The transverse connector may be attached to thespinal rod using crosslinking plates that are well known to thoseskilled in the art and described in the TSRH® Crosslink SurgicalTechnique Manual, which is incorporated by reference herein. It ispreferred that neighboring rods be connected by two transverseconnectors that may be aligned parallel and in spaced relation from oneanother. If the spinal rod is bent, transverse connector 20 ispreferably attached to the spinal rod at a location other than the“peak” of the curved section of the rod so that additional stress is notplaced at that location.

An embodiment of connector 16 is illustrated in FIG. 4. The connectorpreferably includes a fastening end 50 and a receiving end 54 oppositethe fastening end. The fastening end may be a threaded end containingmale machine threads 52 that are adapted to engage a fastener. Thefastener is preferably a nut. The receiving end preferably includes afirst arm 56 and a second arm 58 that together form a U-shaped borehole62. The first arm has a tip 72 and the second arm has a tip 74 (eachlabeled in FIG. 5), and an opening 60 or open end is preferably definedby the tips of the first and second arm. A slot 64 preferably extendsbetween the receiving end and the fastening end. The slot may extendfrom borehole 62 proximate the receiving end to a location proximate thefastening end. The slot may terminate in an enlarged opening 66 withinthe receiving end. The borehole is preferably adapted to receive aspinal rod 12 such that the first and second arms of the receiving endsurround more than about half of a circumferential portion of the spinalrod.

The connector preferably does not completely surround the perimeter ofthe spinal rod. The unsurrounded portion of the spinal rod is preferablyexposed from the open end 60 of the U-shaped borehole and may extendfrom the borehole through the open end. It is preferred that componentmass be placed around only slightly greater than one-half of thecircumference of the spinal rod to minimize the profile width of theconstruct. In this manner, the impingement of the construct upon thefusion mass is lessened, thereby reducing irritation of the surroundingtissue and facilitating the development of a correct spinal fusion in aminimal amount of time. Conventional assemblies tend to completelysurround the spinal rod with component mass, causing a relativelygreater impingement upon the fusion mass, which may interfere withfusion development.

The angle 68 in FIG. 4 is defined by the circumferential portion of aspinal rod that is surrounded by the first arm, second arm, and the endof slot 64. The angle 68 is preferably less than about 2π radians (e.g.,360° around the cross-section of the spinal rod) and greater than aboutπ radians (e.g., 180° around the cross-section of the spinal rod). It ispreferred that more than about half of the circumferential portion thespinal rod be surrounded by a portion of the receiving end (e.g., firstarm, second arm, end of slot 64) to allow the spinal rod to beadequately secured within the borehole. If less than half of thecircumferential portion of the spinal rod were surrounded by thereceiving end, forces resulting from spinal deformations might tend topull the spinal rod from within borehole 62. First arm 56 and second arm58 preferably engage the surface of greater than about half of thecircumferential portion of the spinal rod.

The first arm and the second arm preferably each have an outside surfacethat is slightly tapered such that the distance between the outsidesurfaces of the arms narrows in a direction from tips 72 and 74 to thefastening end 50. The taper of the outside surfaces of the armspreferably defines a locking angle 70. Locking angle 70 is preferably aconical angle, although it may be formed within a substantially flatwedge instead. Locking angle 70 is preferably less than about 30°, morepreferably less than about 25°, and more preferably still between about1° and about 20°.

FIGS. 5 and 6 illustrate the insertion of spinal rod 12 within borehole62 in an embodiment of the invention. The spinal rod is preferablyaxially positioned within the borehole by passing the spinal rod throughopening 60. Slot 64 preferably enables deflection of the first arm andthe second arm relative to one another to allow the width of opening 60to be altered. In the absence of an external force of a selectedmagnitude against the first or second arms, the width of opening 60 ispreferably less than the outside diameter 76 of the spinal rod.Receiving end 54 is preferably adapted to form a “snap-fit” engagementwith the spinal rod that may be realized by forcing the spinal rod intothe inner surfaces of tips 72 and 74 of the first and second arms,respectively. The force against the inner surfaces of the tips 72 and 74preferably causes the arms to slightly deflect in opposite directions,resulting in a slight widening of at least a portion of the slot. Inthis manner, the width of opening 60 may be increased by an amountsufficient to allow the insertion of the spinal rod through opening 60and into the borehole. Once the spinal rod is fully inserted within theborehole (as shown in FIG. 6), the arms preferably move back toward oneanother, causing the slot to narrow to its initial, unstressed width. Ifthe diameter of the spinal rod is slightly greater than that of theborehole, the arms may remain slightly deflected and the slot may remainslightly widened after the spinal rod is snapped into the borehole. Itis generally preferred that the diameter of the spinal rod and thediameter of the borehole be equal.

In an embodiment of the invention, connector 16 connects the spinal rodto a fixation component that engages a portion of the spine. Thefixation component preferably includes a fixation device such as a bonescrew, hook, transverse connector, or similar device. The fixationcomponent preferably includes a body 80 having a tapered cavity intowhich connector 16 may be inserted. The tapered cavity preferably tapersin a direction that is substantially perpendicular to the longitudinalaxis of the fixation component. The tapered cavity preferably has afirst end 84, a second end 86, and an inside surface 82. The insidesurface 82 is preferably tapered at an angle that corresponds to lockingangle 70. The tapered cavity preferably narrows in a direction fromfirst end 84 to second end 86. The tapered cavity is preferably sized sothat fastening end 50 and a portion of receiving end 54 may be insertedwithin the tapered cavity through an aperture proximate the first end.The outer width of the receiving end proximate tips 72 and 74 ispreferably slightly greater than the width of the aperture proximate thefirst end, thereby inhibiting the complete insertion of the receivingend into the tapered cavity.

Fastener 18 may be a hex nut and preferably contains female threading19, which is sized to fit the male machine threads of the fastening end50. The nut preferably engages fastening end 50 and body 80 wherebyrotating the fastener in a tightening direction creates a tensile forcein the connector in direction 88. Tightening of the fastener preferablymoves the connector within the tapered cavity in a direction from firstend 84 to second end 86, thereby creating an interference fit betweenthe arms of the receiving end and inside surface 82. As the fastener istightened, the arms are preferably deflected toward one another suchthat the slot is narrowed and the arms of the receiving end exert acompressive force against the spinal rod disposed within the borehole.

The magnitude of the compressive force exerted by the receiving end onthe spinal rod is preferably variable as a function of the degree towhich the fastener is tightened. The fastener may be selectivelytightened so that the connector is “loosely” engaged to the spinal rod.The “loose” engagement preferably fixes the position of the connector onthe rod in the absence of a selected force against the connector, whileallowing the connector to slide over the surface of the rod uponreceiving a distraction force. For instance, the fastener may bepartially tightened to loosely attach a connector and fixation deviceonto the rod at a selected location. A distraction force may be appliedto the connector to move the connector to a selected location on therod, and the fastener may then be fully tightened to maintain theconnector at the selected location.

The arms 56 and 58 preferably exert a clamping force onto “oppositesides” of the rod (i.e., sections of the outer surface of the spinal rodthat are separated by about 180°). The engagement between the arms 56and 58 and the “opposite sides” of the spinal rod preferably “centers”the rod within the borehole as shown in FIG. 6 so that substantially nogaps exist between the inner surface of the arms and the spinal rod. Therod may be constrained on opposing sides in this manner to providefurther resistance to forces that might otherwise result in axialmovement of the rod. When the arms 56 and 58 are deflected to engage thespinal rod, the receiving end preferably forms a “locking taper”engagement with the spinal rod. A “locking taper” engagement is taken tomean a largely irreversible deflection of the receiving end. That is, ifthe fastener becomes loose after the receiving end has been compressedabout the spinal rod, the clamping force exerted by the receiving endwill be maintained to fixably hold the spinal rod within the borehole.

In an embodiment of the invention depicted in FIG. 7, a transverseconnector 20 is disposed between a pair of spinal rods in spacedrelation to secure the rods at a fixed distance 90. The spinal rods arefixed within the borehole of a connector in the manner depicted in FIGS.5 and 6 and described above. The transverse connector may include abeveled surface between body 80 and a reduced section 92. Reducedsection 92 preferably has a smaller width or diameter than body 80 toallow the reduced section to be bent more easily. Reduced section 92 oftransverse connector 20 may be bent to achieve slight variation in thedistance between spinal rods. The bending of the transverse connectormay be accomplished using a rod bender and a method well known to thoseskilled in the art. Alternately, the transverse connector may have asubstantially constant width or diameter such that the width of section92 and the width of body 80 are approximately equal.

The fixation component may include a bone screw that is used to correctthe angle 32 between vertebrae. It is preferred that the bone screw beadapted to pivot about the spinal rod to form an oblique angle betweenthe longitudinal axis of the spinal rod and the shank of the bone screw.The bone screw preferably can be pivoted in either direction 96 ordirection 98 such that an oblique angle between about 90° and about 60°is formed between the shank and the longitudinal axis of the spinal rod.Other fixation devices (e.g., hooks) may be pivoted with respect thespinal rod in the same manner. As illustrated in FIG. 8, the taperedcavity may contain an engaging side 100 adapted to contact flat 102 ofconnector 16 to limit the pivoting of a fixation device (e.g., bonescrew) about the spinal rod within a selected range, thereby preventinga gross misalignment that might complicate the assembly of the constructduring a surgical procedure.

Body 80 preferably includes a top section 104 and a bottom section 106that together form a U-shaped yoke 112 that is substantiallyperpendicular to inside surface 82 of the tapered cavity. The fixationcomponent may pivot about the spinal rod. The edges of top section 104and/or bottom section 106 may contact the spinal rod to prevent thepivoting of the fixation component about the spinal rod beyond aselected degree. Top section 104 preferably contains a curved edge 108,and bottom section 106 preferably contains a curved edge 110. Curvededges 108 and 110 preferably increase the degree that the fixationcomponent can pivot and allow a fixation device (e.g., bone screw 14) toform an angle within a selected range that is perpendicular with oroblique to the spinal rod.

In an embodiment of the invention, body 80 is laterally offset from thespinal rod. Body 80 may contain a spacer 114 that extends laterally tooffset a fixation component from the spinal rod. Offsetting a fixationcomponent from the spinal rod may reduce the degree that the spinal rodmust be contoured for proper positioning of bone screws (e.g., pediclescrews) in regions of the spine such as the lower lumbar region. Theoffset between the fixation component and the spinal rod may be equal tothe width of the spacer. The offset is preferably less than about 15 mm,more preferably less than about 10 mm, and more preferably still betweenabout 3 mm and about 9 mm.

The spacer may contain a tapered cavity for receiving connector 16 asillustrated in FIG. 9. In an embodiment, the spacer contains a firstplurality of protrusions or teeth that are adapted to form an engagementwith a second plurality of protrusions or teeth 120 disposed on asurface of a fixation device. The teeth of the spacer and the teeth ofthe fixation device preferably are radially spaced at a fixed spacing118. The teeth of the spacer and the protrusions of the fixation devicepreferably form a complementary fit such that adjacent, opposing teethcontact one another over interface length 116 when fastener 18 istightened. The complementary engagement of the teeth preferably inhibitsand/or prevents the fixation device from rotating about spacer 114,thereby fixing the angle formed between the fixation device and thespinal rod.

An embodiment including a reversible fixation device is illustrated inFIG. 10. The body 80 of the hook preferably includes a first U-shapedyoke 137 disposed on a first side 134 of the body and a second U-shapedyoke 138 disposed on a second side 136 of the body. A cavity 132preferably extends through the body from the first side 134 to thesecond side 136. The cavity preferably contains a pair of tapered innersurfaces 133 and 135 that taper in opposite directions such that thecavity narrows in a direction from the first side 134 to the middle ofthe cavity and narrows in a direction from the second side 136 to themiddle of the cavity. The tapered inner surfaces preferably eachterminate in an engaging portion 130 disposed in the middle of thecavity. Connector 16 may be positioned within the cavity so that thereceiving end extends from either first side 134 as shown in FIG. 10B orfrom second side 136 as shown in FIG. 10C. Thus, the reversible hook maybe mounted so that either first side 134 or second side 136 is proximatethe spinal rod, with the hook directed toward either the caudal orcranial direction in each case. The fixation component may contain aslot 109 through which the fastening end of the connector may beinserted during assembly of the construct. The engaging portion 130preferably engages the outer surface of the receiving end to limit theextent to which the receiving end may be inserted into cavity 132.Fastener 18 preferably engages body 80 proximate the engaging portion.

An alternate embodiment including a spacer 114 is illustrated in FIG.11. The spacer preferably surrounds a portion of connector 16 andcontains a tapered surface 140 corresponding to the outside surface ofthe arms of the receiving end. As fastener 18 is tightened, theconnector is preferably drawn within the spacer whereby surface 140engages and exerts a clamping force against the outer surface of thereceiving end. A tensile force created by the tightening of fastener 18preferably maintains the spacer in a fixed position between body 80 andthe spinal rod. The tapered surface 140 may terminate in an engagingsurface 142 that engages the receiving end, thereby limiting the extentto which the receiving end may be drawn within the spacer. The receivingend preferably forms a “pinch clamp” about the spinal rod, wherein thetips 72 and 74 of the arms terminate slightly beyond a vertical axis144, which extends through the center of the spinal rod. The fastenermay be fully tightened to create a selected offset length 145 that ispreferably between about 2 mm and about 10 mm.

To surgically install spinal fixation system 10, the threaded end ofconnector 16 is preferably inserted through the tapered cavity of aspinal fixation component and fastener 18 is loosely threaded onto thethreaded end. The spinal fixation component is then attached to thespine via a hook or screw in a selected location. A plurality of spinalfixation components may be attached to the spine in like manner. Spinalrod 11 may be contoured to match the desired curvature of the spine andplaced into the surgical opening. The spinal rod is preferably snappedwithin the borehole of the connector of each spinal fixation component.The spine is preferably manipulated such that each of the vertebra is ata selected angle and height relative to neighboring vertebrae and theneach fastener 18 is fully tightened to fixably secure the spinal rodinto the borehole of each connector and to secure each of the spinalfixation devices at a selected angle relative to the spinal rod. It isgenerally preferred that the only assembly of system components thatoccurs within the surgical wound is (a) the snapping of the spinal rodwithin one or more connectors and (b) the final tightening of one ormore fasteners that have already been engaged with the fastening end.Each of the fasteners is preferably tightened with a torque of at least150 lb-in. One or more transverse connectors may be added acrossneighboring spinal rods for support to increase the strength of theoverall construct and maintain the spinal rods at a fixed distance fromone another.

In an alternate embodiment, each connector and spinal fixation componentcan be pre-assembled on the spinal rod prior to the implantation of therod into the surgical wound. A connector may first be snapped onto thespinal rod. A fixation component may be added onto the connector suchthat the fastening end of the connector extends through the taperedcavity and the arms of the receiving end contact the inner surface ofthe tapered cavity. The fastener is preferably positioned on thefastening end and partially tightened to maintain the connector andfixation component engaged with the spinal rod. The fastener ispreferably loosely secured on the fastening end to allow the connectorand fixation component to slide along the length of the rod when aselected force is applied to the connector. The spinal rod may becontoured as necessary, and the pre-assembled system may be insertedwithin the surgical wound. The location of the spinal fixationcomponents may be adjusted along the length of the rod as necessary, andthe construct may be connected to the spine via fixation devices. Once afixation component is placed at a selected location, its correspondingfastener may be fully tightened to fix its location. Fixation componentsmay be added to or deleted from the construct as necessary withoutaltering the position of the spinal rod or other fixation components.

In an alternate embodiment, the system may be partially pre-assembledsuch that a number of connectors are initially snapped onto the spinalrod. Fixation components may be inserted within the surgical wound andconnected to the spine at selected locations via fixation devices. Therod may be selectively contoured and inserted within the surgical woundand aligned proximate the spine. A connector is preferably slid alongthe rod to a selected location proximate a fixation component on thespine, and the fastening end of the connector is inserted through thetapered cavity of the fixation component. A fastener may be placed onthe fastening end to clamp the connector onto the spinal rod and tosecure the fixation component therebetween. Additional connectors andfixation components may be secured to the spinal rod in like manner.

After the rod is implanted into the surgical wound, it may be necessaryto add or delete a fixation component. Conventional systems tend torequire that the spinal rod be removed from the surgical wound to allowa fixation component to be threaded onto or removed from the rod. Inaddition, fixation components of conventional systems may have to beremoved from the construct to slide the added fixation component to aselected position. Connector 16 is preferably snapped onto the spinalrod at a selected location. Thus, a connector and any fixation device(e.g., screw, hook, transverse connector) may be added to the spinal rodwithout removing fixation components from the spinal rod or removing thespinal rod from the surgical wound. In the same manner, a connector andfixation device may be removed from the spinal rod without altering theposition of the spinal rod or adjacent connectors. The fastener 18 maybe loosened and a tool may be used to unclamp the receiving end of theconnector from the spinal rod, thereby eliminating the need to slide thecomponent off the end of the spinal rod as in some conventional systems.

Further modifications and alternative embodiments of various aspects ofthe invention will be apparent to those skilled in the art in view ofthis description. Accordingly, this description is to be construed asillustrative only and is for the purpose of teaching those skilled inthe art the general manner of carrying out the invention. It is to beunderstood that the forms of the invention shown and described hereinare to be taken as the presently preferred embodiments. Elements andmaterials may be substituted for those illustrated and described herein,parts and processes may be reversed, and certain features of theinvention may be utilized independently, all as would be apparent to oneskilled in the art after having the benefit of this description of theinvention. Changes may be made in the elements described herein withoutdeparting from the spirit and scope of the invention as described in thefollowing claims.

What is claimed is:
 1. An implant system for a spine, comprising: aconnector comprising a receiving end and a fastening end, the receivingend comprising a surface that defines an opening with an open side; arod positionable within the opening, wherein a portion of the surface ofthe connector contacts the rod during use; a bone screw comprising abody, wherein the body comprises a cavity, and wherein a portion of theconnector is positionable in the cavity during use; a spacer configuredto offset the rod from the body by a desired distance, wherein at leasta portion of the fastening end of the connector is configured to passthrough the spacer, and wherein a surface of the spacer is configured toengage at least a portion of the receiving end; and a fastenerconfigured to engage the body and a portion of the fastening end tocouple the rod to the connector and the connector to the bone screw. 2.The implant system of claim 1, wherein the desired distance between thebody and a closest portion of the rod is greater than about 3millimeters and less than about 15 millimeters.
 3. The implant system ofclaim 1, wherein the desired distance between the body and a closestportion of the rod is greater than about 3 millimeters and less thanabout 10 millimeters.
 4. The implant system of claim 3 wherein thereceiving end comprises a tapered outer surface that substantiallycorresponds to the tapered cavity to provide a large contact areabetween the receiving end and the tapered cavity during use.
 5. Theimplant system of claim 1, wherein the body comprises a surface havingprotrusions and the spacer comprises a surface having teeth, wherein thespacer is rotatable relative to the body before the fastener secures therod to the connector and the connector to the body, and wherein theprotrusions engage the teeth to inhibit rotation of the spacer relativeto the body after the fastener secures the rod to the connector and theconnector to the body.
 6. The implant system of claim 1, wherein a widthof the opening is changeable by changing a position of the fastenerrelative to the body.
 7. The implant system of claim 1, wherein theconnector comprises a slot in the receiving end in communication withthe opening.
 8. The implant system of claim 1, wherein the spacercomprises a tapered cavity and wherein the tapered cavity is adapted tocontact a portion of the receiving end and impart a compressive forceagainst the receiving portion to fixedly couple the rod within theopening.
 9. The implant system of claim 1, wherein the fastener is athreaded nut, and wherein the fastening end comprises threading adaptedto engage the nut.
 10. The implant system of claim 1, wherein thefastener is a threaded nut and the fastening end comprises threadingadapted to engage the nut, wherein tightening the nut causes movement ofthe receiving end within a cavity of the spacer, wherein a portion of asurface of the spacer that defines the cavity exerts a compressive forceagainst an outer surface of the receiving end, and wherein thecompressive force couples the connector to the rod.
 11. The implantsystem of claim 1, wherein the rod is coupled to the connector withinthe opening, and wherein the portion of the circumferential section ofthe rod that is coupled to the surface of the connector is greater thanabout π radians and less than about 2π radians.
 12. The implant systemof claim 1, wherein the spacer comprises a channel, and wherein aportion of the rod is positioned in the channel during use.
 13. Theimplant system of claim 1, wherein the body comprises a cavity, andwherein a portion of the spacer is positionable in the cavity duringuse.
 14. The implant system of claim 1, wherein the body comprises atapered cavity, wherein a portion of the spacer is positionable in thetapered cavity during use, and wherein a surface of the spacer has ataper that substantially corresponds to a taper of the tapered cavity toprovide a large contact area between the tapered cavity and the portionwhen the portion is inserted into the tapered cavity.
 15. The implantsystem of claim 1, wherein the opening of the connector is sized toallow the connector to be snapped onto the rod.
 16. The implant systemof claim 1, wherein the opening is sized to allow the connector to berepositioned along an axial length of the rod after the rod is snappedinto the opening.
 17. The implant system of claim 1, wherein the rod isinsertable into the opening of the connector, wherein the connector ismoveable along a portion of a length of the rod to a desired position,and wherein the fastener is configured to secure the connector to therod to inhibit movement of the rod relative to the connector.
 18. Theimplant system of claim 1, wherein the bone screw comprises a threadedshank.
 19. The implant system of claim 1, wherein the bone screwcomprises a non-threaded shank.
 20. The implant system of claim 1,wherein the bone screw comprises a tap relief to facilitate insertioninto bone.
 21. An implant system for a spine, comprising: a connectorcomprising a receiving end and a fastening end, the receiving endcomprising a surface that defines an opening in the connector with anopen side, wherein the opening is sized to accept a rod, and wherein theconnector comprises a slot in communication with the opening thatfacilitates compression of the receiving end against a rod positioned inthe opening; a bone screw comprising a body, wherein the body comprisesa body opening, and wherein a portion of the connector is positioned inthe body opening during use; and a fastener adapted to engage the bodyand a portion of the fastening end to couple the connector to the bonescrew.
 22. The implant system of claim 21, wherein a portion of the bodyopening is configured to engage the receiving end of the connector toallow for compression of the opening when the fastener couples theconnector to the bone screw.
 23. The implant system of claim 21, whereinthe body opening comprises a recess that allows a portion of a rodpositioned in the connector to be recessed in the body when the fastenercouples the connector to the bone screw.
 24. The implant system of claim21, wherein the body opening comprises a recess that allows a portion ofa rod positioned in the connector to be recessed in the body when thefastener couples the connector to the bone screw, and wherein the recessis configured to allow the rod to be angulated at a desired anglerelative to a shaft of the bone screw.
 25. The implant system of claim21, further comprising a spacer positioned in working relation to thebody opening, and wherein a portion of the spacer is configured toengage the receiving end of the connector to allow for compression ofthe opening when the fastener couples the connector to the bone screw.26. The implant system of claim 21, further comprising a spacerpositioned in working relation to the body opening, wherein a portion ofthe spacer is configured to engage the receiving end of the connector toallow for compression of the opening when the fastener couples theconnector to the bone screw, wherein the body comprises a surface havingprotrusions and the spacer comprises a surface having teeth, wherein thespacer is rotatable relative to the body before the fastener secures theconnector to the body.
 27. The implant system of claim 21, furthercomprising a spacer positioned in a recess of the body opening, andwherein a portion of the spacer is configured to engage the receivingend of the connector to allow for compression of the opening when thefastener couples the connector to the bone screw.
 28. The implant systemof claim 21, wherein the body opening comprises a tapered cavity andwherein a surface of the body defining the tapered cavity is configuredto contact a portion of the receiving end.
 29. The implant system ofclaim 21, wherein the body opening comprises a tapered cavity, wherein asurface of the body defining the tapered cavity is configured to contacta portion of the receiving end, and wherein the receiving end comprisesa tapered outer surface that substantially corresponds to the taperedcavity to provide a large contact area between the receiving end and thetapered cavity during use.
 30. The implant system of claim 21, whereinthe fastener is a threaded nut, and wherein the fastening end comprisesthreading adapted to engage the nut.
 31. The implant system of claim 21,wherein the bone screw comprises a threaded shank.
 32. The implantsystem of claim 21, wherein the bone screw comprises a non-threadedshank.
 33. The implant system of claim 21, wherein the bone screwcomprises a tap relief to facilitate insertion into bone.
 34. An implantsystem for a spine, comprising: a connector comprising a receiving endand a fastening end, the receiving end comprising a surface that definesan opening with an open side, and wherein a width of the opening isadjustable; a rod positionable within the opening such that a portion ofa circumferential section of the rod is coupled to the surface of thereceiving end; a bone screw comprising a body, the body comprising acavity having an inner surface, and wherein the connector is adapted tobe at least partially disposed within the cavity such that the innersurface of the cavity engages a portion of the receiving end; and afastener adapted to engage the body and a portion of the fastening endto couple the rod to the connector and the connector to the bone screw.35. The system of claim 34, wherein the rod is coupled to the connectorwithin the opening, and wherein the portion of the circumferentialsection of the rod that is coupled to the surface of the connector isgreater than about π radians and less than about 2π radians.
 36. Thesystem of claim 34, wherein a rod is configured to be inserted throughthe opening of the connector, and wherein the connector may be movedalong a portion of a length of the rod to a desired position.
 37. Thesystem of claim 34, wherein the rod is insertable into the opening ofthe connector, wherein the connector is moveable along a portion of alength of the rod to a desired position, and wherein the fastener isconfigured to secure the connector to the rod to inhibit movement of therod relative to the connector.
 38. The system of claim 34, wherein thecavity comprises a recess, and wherein the recess is configured to allowthe rod to be angled at a desired angle relative to the bone screw priorto use of the fastener to secure the rod to the connector and theconnector to the bone screw.
 39. The system of claim 34, wherein a widthof the opening is changeable by changing a position of the fastenerrelative to the body.
 40. The system of claim 34, wherein the connectorcomprises a slot in the receiving end in communication with the opening.41. The system of claim 34, wherein the receiving end comprises atapered outer surface that substantially corresponds to the taperedcavity to provide a large contact area between the receiving end and thetapered cavity during use.
 42. The system of claim 34, wherein the bodyopening comprises a tapered cavity and wherein a surface of the bodydefining the tapered cavity is configured to contact a portion of thereceiving end.
 43. The system of claim 34, wherein the opening is sizedto allow the connector to be repositioned along an axial length of therod after the rod is snapped into the opening.
 44. The system of claim34, wherein a portion of the body opening is configured to engage thereceiving end of the connector to allow for compression of the openingwhen the fastener couples the connector to the bone screw.
 45. Thesystem of claim 34, wherein the body opening comprises a recess thatallows a portion of a rod positioned in the connector to be recessed inthe body when the fastener couples the connector to the bone screw. 46.An implant system for a spine, comprising: a connector comprising areceiving end and a fastening end, the receiving end comprising asurface that defines an opening with an open side; a rod positionablewithin the opening such that a portion of a circumferential section ofthe rod is coupled to the surface of the receiving end; a bone screwcomprising a body, the body comprising a cavity having an inner surface,and wherein the connector is adapted to be at least partially disposedwithin the cavity such that the inner surface of the cavity engages aportion of the receiving end; a fastener adapted to engage the body anda portion of the fastening end to couple the rod to the connector andthe connector to the bone screw; and a slot in the receiving end, theslot configured to allow a width of the opening to change during usewhen the fastener is adjusted.
 47. The system of claim 46, wherein therod is insertable into the opening of the connector, wherein theconnector is moveable along a portion of a length of the rod to adesired position, and wherein the fastener is configured to secure theconnector to the rod to inhibit movement of the rod relative to theconnector.
 48. The system of claim 46, wherein the cavity comprises arecess, and wherein the recess is configured to allow the rod to beangled at a desired angle relative to the bone screw prior to use of thefastener to secure the rod to the connector and the connector to thebone screw.
 49. The system of claim 46, wherein the receiving endcomprises a tapered outer surface that substantially corresponds to thetapered cavity to provide a large contact area between the receiving endand the tapered cavity during use.
 50. The system of claim 46, whereinthe body opening comprises a tapered cavity and wherein a surface of thebody defining the tapered cavity is configured to contact a portion ofthe receiving end.
 51. An implant system for a spine, comprising: aconnector comprising a receiving end and a fastening end, the receivingend comprising a surface that defines an opening with an open side; arod positionable within the opening such that a portion of acircumferential section of the rod is coupled to the surface of thereceiving end; a bone screw comprising a body, the body comprising acavity having an inner surface, and wherein the connector is adapted tobe at least partially disposed within the cavity such that the innersurface of the cavity engages a portion of the receiving end, andwherein the cavity of the body is a tapered cavity and wherein thetapered cavity is adapted to contact a portion of the receiving end andimpart a compressive force against the portion of the receiving end tofixably couple the rod within the opening; and a fastener adapted toengage the body and a portion of the fastening end to couple the rod tothe connector and the connector to the bone screw.
 52. The system ofclaim 51, wherein the rod is insertable into the opening of theconnector, wherein the connector is moveable along a portion of a lengthof the rod to a desired position, and wherein the fastener is configuredto secure the connector to the rod to inhibit movement of the rodrelative to the connector.
 53. The system of claim 51, wherein thecavity comprises a recess, and wherein the recess is configured to allowthe rod to be angled at a desired angle relative to the bone screw priorto use of the fastener to secure the rod to the connector and theconnector to the bone screw.
 54. The system of claim 51, wherein a widthof the opening is changeable by changing a position of the fastenerrelative to the body.
 55. The system of claim 51, wherein the connectorcomprises a slot in the receiving end in communication with the opening.56. The system of claim 51, wherein the receiving end comprises atapered outer surface that substantially corresponds to the taperedcavity to provide a large contact area between the receiving end and thetapered cavity during use.
 57. The system of claim 51, wherein thereceiving end comprises a tapered outer surface that substantiallycorresponds to the tapered cavity to provide a large contact areabetween the receiving end and the tapered cavity during use.
 58. Animplant system for a spine, comprising: a connector comprising areceiving end and a fastening end, the receiving end comprising asurface that defines an opening with an open side; a rod positionablewithin the opening such that a portion of a circumferential section ofthe rod is coupled to the surface of the receiving end; a bone screwcomprising a body, the body comprising a cavity having an inner surface,and wherein the connector is adapted to be at least partially disposedwithin the cavity such that the inner surface of the cavity engages aportion of the receiving end; and a fastener adapted to engage the bodyand a portion of the fastening end to couple the rod to the connectorand the connector to the bone screw, and wherein the fastener is athreaded nut and the fastening end comprises threading adapted to engagethe nut, and wherein tightening the nut causes movement of the receivingend within the cavity whereby the inner surface of the cavity exerts acompressive force against an outer surface of the receiving end, andwherein the compressive force couples the connector to the rod.
 59. Thesystem of claim 58, wherein the rod is insertable into the opening ofthe connector, wherein the connector is moveable along a portion of alength of the rod to a desired position, and wherein the fastener isconfigured to secure the connector to the rod to inhibit movement of therod relative to the connector.
 60. The system of claim 58, wherein thecavity comprises a recess, and wherein the recess is configured to allowthe rod to be angled at a desired angle relative to the bone screw priorto use of the fastener to secure the rod to the connector and theconnector to the bone screw.
 61. The system of claim 58, wherein a widthof the opening is changeable by changing a position of the fastenerrelative to the body.
 62. The system of claim 58, wherein the connectorcomprises a slot in the receiving end in communication with the opening.63. The system of claim 58, wherein the receiving end comprises atapered outer surface that substantially corresponds to the taperedcavity to provide a large contact area between the receiving end and thetapered cavity during use.
 64. The system of claim 58, wherein the bodyopening comprises a tapered cavity and wherein a surface of the bodydefining the tapered cavity is configured to contact a portion of thereceiving end.
 65. An implant system for a spine, comprising: aconnector comprising a receiving end and a fastening end, the receivingend comprising a surface that defines an opening with an open side; arod positionable within the opening such that a portion of acircumferential section of the rod is coupled to the surface of thereceiving end; a bone screw comprising a body, the body comprising acavity having an inner surface, and wherein the connector is adapted tobe at least partially disposed within the cavity such that the innersurface of the cavity engages a portion of the receiving end, andwherein the cavity comprises a recess, and wherein a portion of the rodis positioned within the recess during use; and a fastener adapted toengage the body and a portion of the fastening end to couple the rod tothe connector and the connector to the bone screw.
 66. The system ofclaim 65, wherein the cavity comprises a recess, and wherein the recessis configured to allow the rod to be angled at a desired angle relativeto the bone screw prior to use of the fastener to secure the rod to theconnector and the connector to the bone screw.
 67. The system of claim65, wherein a width of the opening is changeable by changing a positionof the fastener relative to the body.
 68. The system of claim 65,wherein the connector comprises a slot in the receiving end incommunication with the opening.
 69. The system of claim 65, wherein thereceiving end comprises a tapered outer surface that substantiallycorresponds to the tapered cavity to provide a large contact areabetween the receiving end and the tapered cavity during use.
 70. Thesystem of claim 65, wherein the body opening comprises a tapered cavityand wherein a surface of the body defining the tapered cavity isconfigured to contact a portion of the receiving end.
 71. An implantsystem for a spine, comprising: a connector comprising a receiving endand a fastening end, the receiving end comprising a surface that definesan opening with an open side, and wherein the opening is sized to allowthe connector to be snapped onto the rod; a rod positionable within theopening such that a portion of a circumferential section of the rod iscoupled to the surface of the receiving end; a bone screw comprising abody, the body comprising a cavity having an inner surface, and whereinthe connector is adapted to be at least partially disposed within thecavity such that the inner surface of the cavity engages a portion ofthe receiving end; and a fastener adapted to engage the body and aportion of the fastening end to couple the rod to the connector and theconnector to the bone screw.
 72. The system of claim 71, wherein the rodis insertable into the opening of the connector, wherein the connectoris moveable along a portion of a length of the rod to a desiredposition, and wherein the fastener is configured to secure the connectorto the rod to inhibit movement of the rod relative to the connector. 73.The system of claim 71, wherein the cavity comprises a recess, andwherein the recess is configured to allow the rod to be angled at adesired angle relative to the bone screw prior to use of the fastener tosecure the rod to the connector and the connector to the bone screw. 74.The system of claim 71, wherein a width of the opening is changeable bychanging a position of the fastener relative to the body.
 75. The systemof claim 71, wherein the connector comprises a slot in the receiving endin communication with the opening.
 76. The system of claim 71, whereinthe receiving end comprises a tapered outer surface that substantiallycorresponds to the tapered cavity to provide a large contact areabetween the receiving end and the tapered cavity during use.
 77. Thesystem of claim 71, wherein the body opening comprises a tapered cavityand wherein a surface of the body defining the tapered cavity isconfigured to contact a portion of the receiving end.
 78. The system ofclaim 71, wherein the connector may be moved along a portion of a lengthof the rod after being snapped onto the rod.
 79. An implant system for aspine, comprising: a connector comprising a receiving end and afastening end, the receiving end comprising a surface that defines anopening with an open side; a rod positionable within the opening suchthat a portion of a circumferential section of the rod is coupled to thesurface of the receiving end; a bone screw comprising a body, the bodycomprising a cavity having an inner surface, and wherein the connectoris adapted to be at least partially disposed within the cavity such thatthe inner surface of the cavity engages a portion of the receiving end,and wherein the cavity comprises a recess, and wherein the recess isconfigured to allow the rod to be recessed in the body when the fastenercouples the rod to the connector and the connector to the bone screw;and a fastener adapted to engage the body and a portion of the fasteningend to couple the rod to the connector and the connector to the bonescrew.
 80. The system of claim 79, wherein the rod is insertable intothe opening of the connector, wherein the connector is moveable along aportion of a length of the rod to a desired position, and wherein thefastener is configured to secure the connector to the rod to inhibitmovement of the rod relative to the connector.
 81. The system of claim79, wherein the recess is configured to allow the rod to be angled at adesired angle relative to the bone screw prior to use of the fastener tosecure the rod to the connector and the connector to the bone screw. 82.The system of claim 79, wherein a width of the opening is changeable bychanging a position of the fastener relative to the body.
 83. The systemof claim 79, wherein the connector comprises a slot in the receiving endin communication with the opening.
 84. The system of claim 79, whereinthe receiving end comprises a tapered outer surface that substantiallycorresponds to the tapered cavity to provide a large contact areabetween the receiving end and the tapered cavity during use.
 85. Thesystem of claim 79, wherein the body opening comprises a tapered cavityand wherein a surface of the body defining the tapered cavity isconfigured to contact a portion of the receiving end.